Methods and apparatus for creating a large area imprint without a seam

ABSTRACT

Embodiments of the present disclosure generally relate to imprint lithography, and more particularly to methods and apparatus for creating a large area imprint without a seam. Methods disclosed herein generally include separating the curing time of the features in a stamp or product from the curing time of the seam and the periphery. The seam and periphery can be cured first or the seam and periphery can be cured last. Additionally, the seam curing operations can be performed on the master, on the stamp, or on the final product.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/924,763, filed Mar. 19, 2018, which herein is incorporated byreference.

BACKGROUND Field

Embodiments of the present disclosure generally relate to imprintlithography, and more particularly to methods and apparatus for creatinga large area imprint without a seam.

Description of the Related Art

Imprint lithography is a contact patterning method that can be used tofabricate nanometer scale patterns. Generally, imprint lithographybegins by creating a template of a pattern. A liquid, such as aphotoresist, is deposited on the substrate to be patterned. Then, thepatterned template is pressed against the liquid to imprint the patternon the substrate. The patterned substrate is then cured to solidify thepatterning in the photoresist on the substrate.

However, conventional imprint lithography methods and apparatus havevarious challenges. For example, conventional imprint lithographymethods are not suitable for large area substrates (greater than 300mm), such as display devices, because conventionally used masters arenot large enough to pattern large area displays. As such, someconventional imprint methods have used multiple masters, which have beenadhered to one another. However, a seam is formed between the mastersand at the periphery, which is then transferred into the patterning onthe substrate. The patterned irregularities at the seams and peripherycan cause decreased device efficiency and even device failure. Forexample, in the case of a light guided panel (LGP), when a seam isimprinted into the LGP, it becomes a surface feature that could director out-couple light out of the LGP. In the case of liquid crystaldisplay (LCD), when a seam is imprinted into the LCD, the viewer willsee the seam in the display.

Therefore, there is a need for improved imprint lithography methods andapparatus that can be used to imprint large area substrates.

SUMMARY

Embodiments of the present disclosure generally relate to imprintlithography, and more particularly to methods and apparatus for creatinga large area imprint without a seam. Methods disclosed herein generallyinclude separating the curing time of the features in a stamp or productfrom the curing time of the seam and the periphery. The seam andperiphery can be cured first or the seam and periphery can be curedlast. Additionally, the seam curing operations can be performed on themaster, on the stamp, or on the final product.

In one embodiment, an imprint lithography method is disclosed. Themethod includes imprinting a stamp material with a plurality of mastersadhered to a backing plate to form a stamp, each master having aplurality of features thereon, and each pair of the plurality of mastershaving a seam therebetween, positioning a mask between an ultravioletlight source and the stamp material, and exposing the stamp material toultraviolet light from the ultraviolet light source to form curedportions and uncured portions of the stamp material.

In another embodiment, an imprint lithography method is disclosed. Themethod includes imprinting a stamp material with a plurality of mastersadhered to a backing plate to form a stamp, each master having aplurality of features thereon, and each pair of the plurality of mastershaving a seam therebetween, imprinting a photoresist material on asubstrate with the stamp, positioning a mask between an ultravioletlight source and the photoresist material, and exposing the photoresistmaterial to ultraviolet light from the ultraviolet light source to formcured portions and uncured portions of the photoresist material.

In yet another embodiment, an imprint lithography method is disclosed.The method includes adhering a plurality of masters to a backing plate,each master having a plurality of features thereon, and each pair of theplurality of masters having a seam therebetween, filling the seambetween each pair of the plurality of masters with a filler material,forming a stamp by imprinting a stamp material with the plurality ofmasters, imprinting a photoresist material over a substrate with thestamp, and removing the stamp from the imprinted photoresist material toform a final product having a positive image of the plurality offeatures and the filled seam thereon.

In yet another embodiment, an imprint lithography apparatus isdisclosed. The apparatus includes a UV transparent backing plate and atleast two masters coupled to the UV transparent backing plate, each ofthe at least two masters having a plurality of features thereon, and theat least two masters having a seam therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIGS. 1A-1F depict various stages of a substrate patterning methodaccording to embodiments disclosed herein.

FIGS. 2A-2D depict various stages of a substrate patterning methodaccording to embodiments disclosed herein.

FIGS. 3A-3D depict various stages of a substrate patterning methodaccording to embodiments disclosed herein.

FIGS. 4A-4B depict various stages of a substrate patterning methodaccording to embodiments disclosed herein.

FIGS. 5A-5F depict various stages of a substrate patterning methodaccording to embodiments disclosed herein.

FIGS. 6A-6F depict various stages of a substrate patterning methodaccording to embodiments disclosed herein.

To facilitate understanding, identical reference numerals have beenused, wherever possible, to designate identical elements that are commonto the Figures. Additionally, elements of one embodiment may beadvantageously adapted for utilization in other embodiments describedherein.

DETAILED DESCRIPTION

Embodiments of the present disclosure generally relate to imprintlithography, and more particularly to methods and apparatus for creatinga large area imprint without a seam. Methods disclosed herein generallyinclude separating the curing time of the features in a stamp or productfrom the curing time of the seam and the periphery. The seam andperiphery can be cured first or the seam and periphery can be curedlast. Additionally, the seam curing operations can be performed on themaster, on the stamp, or on the final product.

The embodiments that follow will refer to methods and apparatus forcreating a large area imprint without a seam. The embodiments are alsouseful to cure similar seam-like challenges at the periphery of themaster, stamp or final product.

FIGS. 1A-1F depict various stages of a substrate patterning methodaccording to embodiments disclosed herein. The method depicted in FIGS.1A-1F provides a master-level solution to seam and periphery challenges.The method begins by adhering a plurality of masters 104 onto a backingplate 102. Two masters 104 are adhered to the backing plate 102 in theembodiment shown in FIG. 1A. The masters 104 have a pattern of features105 thereon. A seam 106 is formed between the two masters 104. The seam106 is filled with a filler material 108, as shown in FIG. 1B.Generally, the filler material 108 will not fill the seam 106 in amanner that results in a completely flat surface. Instead, if the seam106 is underfilled with filler material 108, the seam 106 will becomeconcave, as shown in FIG. 1B. In another embodiment, the seam 106 isoverfilled with filler material 108 and becomes convex.

As shown in FIG. 1C, a stamp material 110 is contacted by the masters104 to form a stamp 112. As shown in FIG. 1D, the stamp 112 is anegative pattern of the masters 104. As such, the stamp 112 includes aconvex portion 114 at the position corresponding to the concave seam 106and negative features 116. The stamp 112 is then used to pattern aphotoresist material 118 which is deposited over a substrate 120, asshown in FIG. 1E, to form a final product 122, as shown in FIG. 1F. Thefinal product 122 includes a photoresist material 118 which has beenpatterned with a plurality of features 125, as well as concave portion127. Since the method includes two transfer imprints, at the stamp leveland the final product level, the final product 122 is a positive imageof the masters 104 and the seam 106.

The filler material 108 is generally any suitable material. In oneexample, the filler material 108 is a polymer. In another example, thefiller material 108 is a low viscosity adhesive that is able to fillgaps or seams that are between about 100 μm and about 500 μm in width,such as a low viscosity silicone. In some examples, the filler material108 is able to fill gaps or seams through capillary action. The stampmaterial 110 is generally any suitable material. In one example, thestamp material 110 is a polydimethyl siloxane material (PDMS), or anyother variation to PDMS that has been spin coated or deposited on asubstrate. In further examples, the stamp material 110 is any softmaterial that functions as an intermediate pattern transfer medium, suchas polyvinyl alcohol (PVA) based. The substrate is generally anysuitable substrate material, including but not limited to, glass, fusedsilica, quartz, poly(methyl methacrylate) (PMMA), polyethyleneterephthalate (PET) and polycarbonate.

In further embodiments, the method includes fewer or additionaloperations to pattern the substrate. For example, in one embodiment, anadditional transfer imprint operation is performed in order to make anegative image of the masters on the substrate. In another embodiment,the masters are used to pattern the substrate directly, and theintermediate transfer imprint operations are eliminated.

FIGS. 2A-2D depict various stages of a substrate patterning methodaccording to embodiments disclosed herein. The method depicted in FIGS.2A-2D provides a stamp-level solution to seam and periphery challengesin which the seam and periphery are cured last. The method begins byadhering a plurality of masters 204 onto a backing plate 202. Twomasters 204 are adhered to the backing plate 202 in the embodiment shownin FIG. 2A. The masters 204 have a pattern of features 205 thereon. Aseam 206 is formed between the two masters 204. As shown in FIG. 2A, theseam 206 is left unfilled. In other embodiments, the seam 206 isunderfilled such that the seam 206 is concave.

Next, shown in FIG. 2B, the masters 204 imprint a stamp material 210.After the masters 204 imprint the stamp material 210, a mask 224 ispositioned between the stamp material 210 and an ultraviolet (UV) lightsource 226, as shown in FIG. 2C. In operation, the mask 224 prevents UVlight from reaching the portion of the stamp material 210 correspondingto the seam 206. Since the UV light from the UV light source 226 doesnot reach the portion of the stamp material 210 corresponding to theseam 206, the seam 206 will be imprinted but not cured in the stampmaterial 210.

After the unmasked portions of the stamp material 210 have been cured,shown as cured portions 228 in FIG. 2D, the masters 204 are removed fromthe stamp material 210 and the uncured portions 230 (corresponding tothe seam 206 and periphery) of the stamp material 210 flow or “relax”until the uncured portions 230 are flat along the surface of thesubstrate 221, as shown in FIG. 2D. After the uncured portions 230 haveflowed and are flat along the surface of the substrate 221, the stampmaterial 210 is cured again with additional UV light to create a stamp212 having features 225 thereon. The stamp 212 can be used to imprint afinal product, such as a large area substrate, without leaving a seam inthe final product.

The stamp material 210 is generally any suitable material. In oneexample, the stamp material 210 is a PDMS material. In another example,the soft stamp material 210 is made from PVA. The substrate 221 isgenerally any suitable substrate material, including but not limited to,glass, PMMA, and polycarbonate.

In another embodiment, the seam 206 is overfilled with a fillermaterial, such as a polymer. As shown in FIGS. 2A-2D the stamp material210 is deposited on a substrate 221; in further embodiments, however,the stamp material 210 is directly coated on the masters 204 and islater removed. In further embodiments, the uncured portions 230 arewashed away instead of subsequently cured. For example, the uncuredportions 230 may be removed using one or more solvents selected toremove the particular stamp material 210. Additionally, furtherembodiments contemplate using a maskless direct write laser system tocure predetermined portions of the material using a focused, narrow beamof radiation. For example, the maskless direct write system can be usedto cure the regions with features during the imprint method. Themaskless direct write laser system then also can be used to cure theseam and periphery regions after the masters have been removed.

In further embodiments, the method includes fewer or additionaloperations to pattern the substrate. For example, in one embodiment, anadditional transfer imprint operation is performed in order to make anegative image of the masters on the substrate. In another embodiment,the masters are used to pattern the substrate directly and theintermediate transfer imprint operations are eliminated.

FIGS. 3A-3D depict various stages of a substrate patterning methodaccording to embodiments disclosed herein. The method depicted in FIGS.3A-3D provides a stamp-level solution to seam and periphery challengesin which the seam and periphery are cured first. The method begins byadhering a plurality of masters 304 onto a backing plate 302. Twomasters 304 are adhered to the backing plate 302 in the embodiment shownin FIG. 3A. The masters 304 have a pattern of features 305 thereon. Aseam 306 is formed between the two masters 304. As shown in FIG. 3A, theseam 306 is left unfilled. In other embodiments, the seam 306 isunderfilled such that the seam 306 is concave.

Next, a stamp material 310 deposited over a substrate 321 is cured. Moreparticularly, a mask 324 is positioned between the stamp material 310and a UV light source 326, as shown in FIGS. 3B-3C. In operation, themask 324 prevents UV light from reaching the portions, shown as uncuredportions 330, of the stamp material 310 that will be imprinted with thefeatures 305. The unmasked portions of the stamp material 310 are cured,shown as cured portions 328. The cured portions 328 correspond to theareas of the seam 306 and periphery. The masters 304 then imprint theuncured portions 330 of the stamp material 310 while the cured portions328 are not imprinted, as shown in FIG. 3C. After being imprinted, theimprinted uncured portions 330 are cured. The masters 304 and backingplate 302 are then removed to form a stamp 312 having features 325thereon, as shown in FIG. 3D. The stamp 312 can be used to imprint afinal product, such as a large area substrate, without leaving a seam inthe final product.

The stamp material 310 is generally any suitable material. In oneexample, the stamp material 310 is a PDMS material. The substrate 321 isgenerally any suitable substrate material, including but not limited to,glass, PMMA, and polycarbonate.

In another embodiment, the seam 306 is overfilled with a fillermaterial, such as a polymer. Further embodiments contemplate using amaskless direct write laser system to cure the regions with featuresbefore the imprint operations. For example, the maskless direct writelaser system is used to cure the seam 306 and periphery regions beforethe masters 304 have imprinted the stamp material 310. Additionally, themaskless direct write laser system can be used to cure the rest of thestamp material 310 after the stamp material 310 has been imprinted bythe masters 304.

As shown in FIGS. 3B-3C, the UV light source 326 is positioned below thestamp material 310. However, in the embodiment shown in FIG. 4A, a UVlight source 426 is positioned above the backing plate 402, the masters404 and the stamp material 410. In this embodiment, the masters 404operate as a self-aligned mask such that the UV light does not reach theportions of the stamp material 410 that are below the masters 404, asshown by uncured portions 430. Accordingly, the backing plate 402comprises any suitable material that is transparent to the wavelength ofthe UV light being used for curing. Suitable backing plate materialsinclude, but are not limited to, glass, quartz, sapphire and fusedsilica. As shown in FIG. 4B, depending on the angle of the UV light, aregion of the stamp material 410 that is cured is generally slightlylarger than the seam 406 to improve the mechanical stability of theimprinted stamp. Stated differently, there is generally an overlappingregion 431 at the edges of the masters 404 such that the region of thestamp material 410 thereunder is cured. Other methods and configurationsare also contemplated to obtain a slight overlap between cured region ofthe stamp material 410 and the masters 404. The size of the overlappingregion 431 is generally selected based on the flexure of the curedregions and the masters 404 to minimize the impact on the pattern offeatures 405, while also achieving seamless or nearly seamless transfer.

The overlapping region 431 is useful to remove or reduce a smallstep-height at the end of the seam 406 that may result when the masters404 transfer the pattern of features 405 into the stamp material 410.After the operation shown in FIG. 4B, subsequent imprint steps are usedto transfer the pattern on the masters 404 to the stamp material 410,which is then cured.

FIGS. 5A-5F depict various stages of a substrate patterning methodaccording to embodiments disclosed herein. The method depicted in FIGS.5A-5F provides a product-level solution to seam and periphery challengesin which the seam and periphery are cured last. The method begins byadhering a plurality of masters 504 onto a backing plate 502. Twomasters 504 are adhered to the backing plate 502 in the embodiment shownin FIG. 5A. The masters 504 have a pattern of features 505 thereon. Aseam 506 is formed between the two masters 504. The seam 506 is filledwith a filler material 508, as shown in FIG. 5B. Generally, the fillermaterial 508 will not fill the seam 506 in a manner that produces acompletely flat surface. Instead, if the seam 506 is overfilled withfiller material 508, the filled seam 506 will become convex, as shown inFIG. 5B. In another embodiment, the filled seam 506 is underfilled withfiller material 508 and becomes concave.

As shown in FIG. 5C, a stamp material 510 is contacted by the masters504 to form a stamp 512. As shown in FIG. 5D, the stamp 512 is anegative pattern of the masters 504. As such, the stamp 512 includes aconcave portion 514 at the position corresponding to the convex seam 506and negative features 516. The stamp 512 is then used to pattern aphotoresist material 518 which is deposited over a substrate 520. Asshown in FIG. 5E, a mask 524 is positioned between the stamp 512 and aUV light source 526. In operation, the mask 524 prevents UV light fromreaching the seam 506 and periphery of the stamp 512, as shown byuncured portion 530, such that the seam and periphery are imprinted, butnot cured. The stamp 512 is then removed and a final product 522 isformed, as shown in FIG. 5F. The final product 522 includes uncuredportion 530 that flows or “relaxes” until the uncured portion 530 isflat along the surface of the substrate 521. After the uncured portion530 has flowed and is flat on the surface of the substrate 521, thefinal product 522 is cured again with additional UV light to create afinal product 522 having features 525 thereon that is without a seam.

As shown in FIGS. 5A-5F the photoresist material 518 is deposited on asubstrate 520; in further embodiments, however, the photoresist material518 is directly coated on the stamp 512 and is later removed. In furtherembodiments, the uncured portion 530 may be washed away instead ofsubsequently cured. Additionally, further embodiments contemplate usinga maskless direct write laser system to cure the regions with featuresduring the imprint method.

FIGS. 6A-6F depict various stages of a substrate patterning methodaccording to embodiments disclosed herein. The method depicted in FIGS.6A-6F provides a product-level solution to seam and periphery challengesin which the seam and periphery are cured first. The method begins byadhering a plurality of masters 604 onto a backing plate 602. Twomasters 604 are adhered to the backing plate 602 in the embodiment shownin FIG. 6A. The masters 604 have a pattern of features 605 thereon. Aseam 606 is formed between the two masters 604. The seam 606 is filledwith a filler material 608, as shown in FIG. 6B. Generally, the fillermaterial 608 will not fill the seam 606 in a manner that provides acompletely flat surface. Instead, if the seam 606 is overfilled withfiller material 608, the filled seam 606 will become convex, as shown inFIG. 6B. In another embodiment, the filled seam 606 is underfilled withfiller material 608 and becomes concave.

As shown in FIG. 6C, a stamp material 610 is contacted by the masters604 to form a stamp 612. As shown in FIG. 6D, the stamp 612 is anegative pattern of the masters 604. As such, the stamp 612 includes aconcave portion 614 at the position corresponding to the convex seam 606and negative features 616. The stamp 612 is then used to pattern aphotoresist material 618 which is deposited over a substrate 620. Asshown in FIG. 6E, a mask 624 is positioned between the stamp 612 and aUV light source 626. In operation, the mask 624 prevents UV light fromreaching the portions, shown as uncured portions 630, of the photoresistmaterial 618 that will be imprinted with the features 616. The unmaskedportions of the photoresist material 618 are cured, shown as curedportions 628. The cured portions 628 correspond to the areas of the seam606 and periphery. The stamp 612 then imprints the uncured portions 630of the photoresist material 618 while the cured portions 628 are notimprinted, as shown in FIG. 6F, to form a final product 622, such as alarge area substrate, without a seam.

The stamp material 610 is generally any suitable material. In oneexample, the stamp material 610 is a PDMS material. The photoresistmaterial 618 is generally any suitable photoresist material. Thesubstrate 620 is generally any suitable substrate material, includingbut not limited to, glass, PMMA, and polycarbonate.

In another embodiment, the seam 606 is overfilled with a fillermaterial, such as a polymer, and a high elasticity stamp material 610 isused. Further embodiments also contemplate using a maskless direct writelaser system to cure the seam 606 and periphery regions before imprint.For example, the maskless direct write laser system is used to cure theseam 606 and periphery regions before the stamp 612 imprints the uncuredportions 630 of the photoresist material 618. Additionally, the masklessdirect write laser system can be used to cure the rest of thephotoresist material 618 after the imprinting has occurred.

The disclosed methods and apparatus are beneficially used to patternnanoscale features on large area substrates, such as 300 nanometer (nm)or greater display devices, with reduced or eliminated patterning issuesat the seams and periphery. For example, the disclosed methods andapparatus can be used imprint a display device with nanofeatures, suchas 100 nm features or 50 nm features, with reduced or eliminatedpatterning issues at the seams and periphery. The disclosed methods andapparatus are useful to pattern Liquid Crystal Displays (LCDs), LightGuide Plates (LGPs), Light Field Plates (LFPs), and Wire Grid Polarizers(WGPs), in addition to other display devices and other optical elementsor films for other applications including automotive applications, oraugmented reality or virtual reality headsets or smart windows. Byreducing or eliminating the patterning irregularities at the seams andperiphery, the functionality of the optical device is generallyimproved. For example, in an LGP, reducing or eliminating theirregularities at the seam and periphery will reduce the light loss fromthe device. In an LCD, reducing or eliminating the irregularities at theseam and periphery will improve the quality of the projected image fromthe display and viewers will not see the patterned seams in the imagebeing projected.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. An imprint lithography method, comprising:providing a plurality of masters disposed on a backing plate, whereinthe plurality of masters includes a first master and a second master,and the plurality of masters includes a seam located between the firstmaster and the second master; and imprinting a stamp material comprisingcured portions and uncured portions with the plurality of masters toform features in the uncured portions of the stamp material, wherein thecured portions of the stamp material comprise a periphery of the stampmaterial.
 2. The method of claim 1, further comprising directingultraviolet light from an ultraviolet light source at the stamp materialto form the cured portions and uncured portions of the stamp material.3. The method of claim 2, wherein a mask is positioned between theultraviolet light source and the stamp material when the ultravioletlight is directed at the stamp material.
 4. The method of claim 2,wherein the plurality of masters are positioned between the ultravioletlight source and the stamp material when the ultraviolet light isdirected at the stamp material.
 5. The method of claim 4, wherein thebacking plate is transparent to the ultraviolet light directed at thestamp material.
 6. The method of claim 2, further comprising: directingadditional ultraviolet light from the ultraviolet light source at thestamp material having the cured portions and uncured portions to curethe uncured portions of the stamp material, wherein the additionalultraviolet light is directed at the stamp material after the stampmaterial is imprinted with the plurality of masters.
 7. The method ofclaim 6, wherein the additional ultraviolet light cures all of theuncured portions of the stamp material.
 8. The method of claim 1,wherein the cured portions further comprise portions of the stampmaterial directly underlying the seam between the first master and thesecond master when the stamp material is imprinted by the plurality ofmasters.
 9. The method of claim 1, further comprising: curing theuncured portions to form a stamp after the stamp material is imprintedwith the plurality of masters; imprinting a photoresist material on asubstrate with the stamp; and removing the stamp from the imprintedphotoresist material to form a patterned final product.
 10. An imprintlithography method, comprising: positioning a plurality of mastersdisposed on a backing plate between an ultraviolet light source and astamp material; and directing ultraviolet light from the ultravioletlight source at the stamp material to form cured portions and uncuredportions of the stamp material, wherein the cured portions of the stampmaterial comprise a periphery of the stamp material and the plurality ofmasters are spaced apart from the stamp material and located between theultraviolet light source and the stamp material when the ultravioletlight is directed at the stamp material.
 11. The method of claim 10,further comprising imprinting the stamp material with the plurality ofmasters to form features in the uncured portions of the stamp material.12. The method of claim 10, wherein the backing plate is transparent tothe ultraviolet light directed at the stamp material.
 13. The method ofclaim 10, wherein the plurality of masters includes a first master and asecond master, the plurality of masters includes a seam located betweenthe first master and the second master, and directing the ultravioletlight includes directing ultraviolet light through the seam to form afirst cured portion of the cured portions.
 14. The method of claim 13,wherein the first cured portion includes a top surface, and directingthe ultraviolet light through the seam comprises directing ultravioletlight at angles other than perpendicular to the top surface.
 15. Themethod of claim 13, wherein the first cured portion includes anoverlapping region directly underlying the first master when the firstcured portion is formed.
 16. The method of claim 13, wherein the firstmaster is spaced apart from the second master by a first distance in afirst direction, the first cured portion extends in the first directionfor a second distance, and the second distance is greater than the firstdistance.
 17. An imprint lithography method, comprising: directingultraviolet light from an ultraviolet light source at a stamp materialto form cured portions and uncured portions of the stamp material,wherein the cured portions of the stamp material comprise a periphery ofthe stamp material; and imprinting the stamp material including thecured portions and the uncured portions with a plurality of masters toform features in the uncured portions of the stamp material.
 18. Themethod of claim 17, further comprising: directing additional ultravioletlight from the ultraviolet light source at the stamp material having thecured portions and uncured portions to cure the uncured portions of thestamp material, wherein the additional ultraviolet light is directed atthe stamp material after the stamp material is imprinted with theplurality of masters.
 19. The method of claim 18, wherein the additionalultraviolet light cures all of the uncured portions of the stampmaterial.
 20. The method of claim 17, further comprising: curing theuncured portions to form a stamp after the stamp material is imprintedwith the plurality of masters; imprinting a photoresist material on asubstrate with the stamp; and removing the stamp from the imprintedphotoresist material to form a patterned final product.